1. Field of the Invention
This invention relates to an inductor for the inductive reheating of metallurgical products. In particular, but not exclusively, this invention applies to the reheating of the edges of blanks for flat products in motion during their rolling on a rolling mill.
2. Description of the Prior Art
Different types of inductors have been developed for these applications and, in particular, the prior art includes magnetic yoke inductors in the shape of a "C", through the opening of which the product to be heated (edges of strip or wires or bars) passes. The free ends of the yoke face one another and are advantageously used as a support for the windings of the excitation electric current conductor, constituting wound magnetic poles with opposite polarities: e.g., French Laid Open patent application No. FR-A-2 489 645-(EDF), French Laid Open patent application No. FR-A-2 555 353-(CEM) or European Laid Open patent application No. EP-A-0 170-556 (EDF).
Another inductor of this type is described in FR-A-2 583 249, which corresponds to U.S. Ser. No. 867,503 cited above, both of which are expressly incorporated herein by reference as if the entire contents thereof were fully set forth herein. This document describes a C-shaped inductor articulated around an axis to allow separation of the two ends of the C, to facilitate the positioning of the inductor on the edge of the flat product, and primarily to keep the ends of the rolled strip, which exhibit a large curvature (ski), from hitting either of the poles of the inductor. For this purpose, one of the legs of the inductor is controlled so that it swings backward, pivoting around the axis of the joint, which increases the clearance and allows a larger cross section for passage of the product.
One of the important characteristics of this inductor is the special design of the joint, to ensure the best possible transmission of the magnetic flux by limiting the heating of the yoke at the level of the joint.
This inductor already has appreciable advantages, but it does not allow a correct reheating of products of varied dimensions and, in particular, of varied thicknesses. The inventors have discovered that, to use articulated C-shaped inductors to reheat products whose thickness is different from that for which these inductors were initially designed, varying the distance between the legs of the C, the results were unsatisfactory, and the efficiency of the heating process decreased.